This application claims benefit of Japanese Application No. 2002-28569 filed in Japan on Feb. 5, 2002, and No. 2002-45938 filed in Japan on Feb. 22, 2002, the contents of which are incorporated by this reference.
The present invention relates to an optical system and an optical apparatus, and more particularly to an optical system comprising a focus-controllable optical element having variable optical properties represented by a variable-shape mirror and optical apparatus comprising said optical system, e.g., video projectors, digital cameras, TV cameras, endoscopes and camera finders.
Referring to conventional lenses formed of polished glass materials, their focal length cannot be varied because they cannot transform by themselves. For this reason, mechanical structures become complicated, which are used to move said lenses or lens groups comprising the same in an axial direction for focusing and zooming.
Since motors, etc. are used to mechanically move some of the lens groups, there are problems such as increased power consumptions, noisy sounds, slow response speeds, and time-consuming movement of lens groups.
Even for photo taking or observations while camera shake is prevented, lens groups are mechanically moved with motors, solenoids, etc., resulting in problems such as increased power consumptions, cost rises due to complicated mechanical structures.
In view of such problems as discussed above, a primary object of the invention is to provide an optical system represented by a lens system comprising a variable-shape mirror having a reflecting surface capable of focusing or a lens system comprising a variable-focus lens, which has limited power consumptions, produces little or no noise and ensures fast response, simple mechanical structure and cost reductions, and optical apparatus comprising such an optical system.
The inventive optical system and apparatus provided to attain the aforesaid object are embodied as follows.
(1) An optical system, characterized by comprising a variable mirror and an aperture stop, wherein the aperture stop satisfies the following condition (601):
0xe2x89xa6|Sm/f|xe2x89xa610xe2x80x83xe2x80x83(601)
where Sm is the distance between the reflecting surface of the variable mirror and the aperture stop as measured along the optical axis of the optical system and calculated on an air basis, and f is the focal length of the optical system except the variable mirror.
(2) An optical system, characterized by comprising a variable mirror and an aperture stop, and satisfying the following condition (599):
39xc2x0xe2x89xa6"PHgr"xe2x89xa660xc2x0xe2x80x83xe2x80x83(599)
where "PHgr" is the angle of incidence of the optical axis of the optical system on the variable mirror.
(3) An optical system, comprising, in order from its object side, an optical element group, a variable mirror or a variable-focus lens, a lens group or an air separation, a zooming group and an optical element group.
(4) An optical system, characterized by comprising a variable mirror and a zooming group having a zooming function, wherein the variable mirror has a focusing function and is located in front of the zooming group.
(5) An optical system having a variable mirror, characterized by a full-open aperture stop located at a position that complies with the following condition (601), wherein a diaphragm having a variable aperture is located at a position different from the position of said aperture stop:
0xe2x89xa6|Sm/f|xe2x89xa610xe2x80x83xe2x80x83(601)
where Sm is the distance between the reflecting surface of the variable mirror and the aperture stop as measured along the optical axis of the optical system and calculated on an air basis, and f is the focal length of the optical system except the variable mirror.
(6) An optical system, comprising a variable mirror, and satisfying the following condition (613):
39xc2x0xe2x89xa6"PHgr"xe2x89xa655xc2x0xe2x80x83xe2x80x83(613)
where "PHgr" is the angle of incidence of the optical axis of the optical system on the variable mirror.
(7) An optical system, comprising a variable mirror and satisfying the following condition (616):
0.5 less than M1/f less than 5xe2x80x83xe2x80x83(616)
where M1 is the distance between the reflecting surface of the variable mirror and the entrance-side first surface of the optical system as measured along the optical axis of the optical system and calculated on an air basis, and f is the focal length of the optical system except the variable mirror.
(8) An optical apparatus comprising an optical system including an optical element having variable optical properties and an image plane, characterized in that to correct said optical system for movement of an image-formation surface in association with a change in the optical element having variable optical properties, the image plane is located in the range of a change in the movement of the image-formation surface in association with the change in the optical element having variable optical properties.
(9) An image pickup system comprising an optical element having variable optical properties and an image pickup device, characterized in that to compensate for a change in the tilt of an image-formation surface in association with a change in the optical element having variable optical properties, the image pickup device is decentered or tilted, thereby compensating for a decrease in image-formation performance in association with the change in the optical element having variable optical properties.
(10) An optical apparatus comprising an optical element having variable optical properties and a display device, characterized in that to compensate for a change in the tilt of an image-formation surface in association with a change in the optical element having variable optical properties, the display device is decentered or tilted, thereby compensating for a decrease in display performance in association with the change in the optical element having variable optical properties.
(11) An optical apparatus comprising an optical system including an optical element having variable optical properties and an image plane, characterized in that the image plane is spaced xcex94M away from the end of the range of a change in the tilt of an image-formation surface in association with a change in the optical element having variable optical properties, wherein xcex94M satisfies the following condition (611):
|xcex94M|xe2x89xa7Df/20xe2x80x83xe2x80x83(611)
where xcex94M is the maximum amount of displacement in an optical axis direction of the optical system of the image plane from the image-formation surface of the optical system, wherein said displacement is caused by a tilt of the image plane, and Df is the focal depth on one side of the optical system.
(12) An optical apparatus comprising an optical element having variable optical properties, an optical device and a fixed image plane, characterized in that to compensate for movement of an image-formation surface in association with a change in the optical element having variable optical properties, the optical device is decentered to tilt the image-formation surface, thereby setting the fixed image plane in the range of a change in the tilt of the image-formation surface in association with the change in the optical element having variable optical properties.
(13) An optical apparatus comprising an optical element having variable optical properties, an optical device and an image plane, characterized in that to compensate for movement of an image-formation surface in association with a change in the optical element having variable optical properties, the optical device is decentered to tilt the image-formation surface, thereby bringing the image plane close to the image-formation surface that moves in association with the change in the optical element having variable optical properties.
(14) An optical apparatus comprising an optical element having variable optical properties and an optical device, characterized in that to compensate for aberrational changes in association with a change in the optical element having variable optical properties, the optical device is decentered to produce aberrations, thereby compensating the optical apparatus for the aberrational changes in association with the change in the optical element having variable optical properties.
(15) An optical apparatus using one or more variable mirrors, characterized in that a shift decentration given by xcex94 is intentionally added to at least one optical surface, optical element or image pickup device in the vertical direction to the Z-axis of the optical apparatus with the proviso that the range represented by 0xe2x89xa6|xcex94|/f less than 1 is satisfied, wherein xcex94 is the amount of the shift decentration added in the vertical direction to the Z-axis, and f is the focal length of an optical system except the variable mirror.
(16) An optical apparatus using one or more variable mirrors, characterized in that a tilt decentration given by Q is intentionally added to at least one optical surface, optical element, image pickup device, display device or image plane with the axis of rotation defined by a straight line vertical to the Z-axis of the optical apparatus, provided that the range represented by 0xe2x89xa6|Q| less than 15 is satisfied, wherein Q is the amount of tilt decentration (in xc2x0) with the axis of rotation defined by the straight line vertical to the Z-axis.
(17) The optical system according to (1), characterized in that said variable mirror has an increased converging action at a near point and a decreased converging action at a far point.
(18) A camera, characterized in that when the optical axis thereof is bent on a long side thereof, the post-bending optical axis is located in a substantially lateral direction of the camera.
(19) A camera, characterized in that when the optical axis thereof is bent on a short side thereof, the post-bending optical axis is located in a substantially longitudinal direction of the camera.
(20) An optical system using at least one variable mirror, characterized in that a tilt decentration is intentionally added to at least one optical surface, optical element, image pickup device or image plane with the axis of rotation defined by a straight line vertical to the Z-axis of the optical system, provided that the range represented by the following condition (103) is satisfied:
0xe2x89xa6|xcexa8| less than 15xe2x80x83xe2x80x83(103)
where xcexa8 is the amount of the tilt decentration added in xc2x0.
(21) An optical system, characterized by comprising an invariable-shape mirror and an aperture stop, wherein the position of the aperture stop satisfies the following condition (601):
0xe2x89xa6|Sm/f|xe2x89xa610xe2x80x83xe2x80x83(601)
where Sm is the distance between the reflecting surface of the mirror and the aperture stop as measured along the optical axis of the optical system and calculated on an air-basis, and f is the focal length of the optical system except the mirror.
(22) An optical system, characterized by comprising an invariable-shape mirror and an aperture stop and satisfying the following condition (599):
39xc2x0xe2x89xa6"PHgr"xe2x89xa660xc2x0xe2x80x83xe2x80x83(599)
where "PHgr" is the angle of incidence of the optical axis of the optical system on the mirror.
(23) An optical system, characterized by comprising an invariable-shape mirror and satisfying the following condition (616):
0.5 less than M1/f less than 5xe2x80x83xe2x80x83(616)
where M1 is the distance between the reflecting surface of the mirror and the entrance-side first surface of the optical system as measured along the optical axis of the optical system and calculated on an air basis, and f is the focal length of the optical system except the mirror.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The invention accordingly comprises the features of the construction, combinations of elements, and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.